1. Field of the Invention
The present invention relates to a translation machine which is capable of building two or more syntaxes of a target language from one inputted sentence of a source language, and more particularly to a translation machine which provides a capability of learning a syntax priority for indicating which of the syntaxes is closer to the desired syntax of a source language.
2. Description of the Related Art
A translation machine known by the inventors is, in general, arranged to have an input unit such as a keyboard for inputting an object sentence of a source language, a translating module for executing an actual translation of the inputted sentence, a central processing unit (main CPU) for controlling the translation module, and a main memory for storing dictionaries such as a main dictionary and a user dictionary, grammatical rules, and tree-structure converting rules. The inputted object sentence is sent to the translating module under the control of the main CPU and is translated into the target sentence by referring to the dictionaries, the grammatical rules and the tree-structure converting rules.
This translation machine analyzes the syntax based on the parts of speech obtained as a result of analyzing the morphemes of the object sentence and by referring to the dictionaries and the grammatical rules and, in many cases, builds two or more syntaxes for one object sentence. Hence, for one object sentence, two or more translated sentences may be normally generated.
On the other hand, as a realistic problem, the translation machine has the following outputting types for the translated sentence.
(a) For one original sentence, just one translated sentence is outputted. PA1 (b) For one original sentence, just one translated sentence is outputted, however, another translated sentence may be serially outputted by a user's operation of the keyboard. PA1 (c) For one original sentence, two or more translated sentences are outputted at one time. PA1 (1) Semantic Analysis PA1 (2) Modifying Relation PA1 (3) Describing Sequence of Grammatical Rules PA1 (4) Scoring of Grammatical Rules PA1 (a) A new word or idiom in the dictionary provided in the translation machine can be registered. PA1 (b) Under a specified condition, a translated part of a word or idiom is outputted. PA1 (c) Controlling the level of complexity at which the syntatic analysis is executed.
If the translation machine uses the output type of (a), the translated sentence appearing for the first is required to be the best of the translated sentences.
If the translation machine uses such a user interface as outputting two or more translated sentences for one original sentence such as the output types (b) and (c), more desirable translated sentences are required to be outputted in sequence. If the used user interface is the type (b), the most desirable one of the translated sentences to be generated by the translation machine should be outputted first. Then, more desirable ones should be outputted in sequence.
If the user interface is the type (c), more desirable translated sentences should be outputted on the display in sequence. For example, more desirable translated sentences should appear from the upper to lower locations on the display.
For this purpose, if two or more syntaxes, that is, translated sentences may be derived from one original sentence, it is necessary to define the priority range of the translated sentences by comparing the translated sentences with each other in light of the translation level.
If the user interface is the type (a), only the translated sentence on the top priority in the defined priority range appears.
Hence, to define the priority range, the following methods have been known.
For method (1), semantic analysis, the concrete method is arranged to write information about a semantic category in a word dictionary and prevent use of such a syntax as having the modified words with different semantic categories when defining the modification between the words in analyzing the syntax.
For method (2), modifying relation, this method is a kind of semantic analysis and is arranged to specify a word to be modified with another word and describe it in the dictionary. When defining the modification between the words in analyzing the syntax, if a certain syntax has a different word to be modified from the description of the dictionary, this syntax is not used.
For method (3), describing sequence of grammatical rules, the "grammatical rules" are the rules for analyzing the syntax indicated in table 2 (to be described later).
By adjusting the describing sequence of the grammatical rules in the dictionary, it is possible to change how easily each of the grammatical rules may apply to the translation. This results in controlling the easiness with which one or more specific syntaxes may be generated to a certain extent. The easiness with which the syntax is generated may be considered to be a basis on which the priority is defined for the syntax.
For method (4), scoring of grammatical rules, by scoring each of the grammatical rules, the total score or the average score of the used grammatical rules is used.
When two or more syntaxes may be built for one original sentence, the methods for defining the priority between these syntaxes have been described. However, these methods have the following shortcomings.
At first, the semantic analysis including a check for a modifying relation is considered. The semantic analysis is a significant process. It is effective to determine that an incorrect syntax is not used on the basis of the semantic analysis. In general, however, the semantic analysis in the translation machine requires a complicated process and a long execution time. Because many syntaxes are normally derived from the original sentence, it is not realistic to execute semantic analysis in light of the long processing time, which would be required. In the case of using the semantic analysis, it is preferable to define which of the syntaxes should take precedence at a previous stage using a simpler method (simpler than semantic analysis).
Further, a known translation machine employs the method for using the grammatical rules indicated in table 2 (to be described later) for defining the priority range of the syntaxes. However, each of the grammatical rules for syntactic analysis is for only a part of the overall syntax. Hence, if a priority coefficient is given to such a grammatical rule, the value derived on the coefficient does not correctly reflect the priority syntax if viewed as an overall sentence or a large part of the sentence. This is also a shortcoming.
The translation machine known by the inventors is, in general, arranged to allow a user to partially change the operation of the machine for achieving a personalized user interface. The contents which can be changed are as follows:
As mentioned above, in the known translation machine, the user may change only the translated part of a word or idiom or adjust the general operation of a certain process in the translating process. In general, when translating a longer original sentence with a larger scaled syntax, by totally grasping the syntax, a human translator (not using a machine) knows from experience the general syntax of the original sentence.
Hence, by extracting experience rules depending on only the form of the syntax and systematizing them, in the machine translation, these experience rules may be powerful information for defining the priority one of the syntaxes derived from one original sentence.
However, since the known translation machine does not use the experience information, if the user having excellent grammatical skill desires the translation machine to select his or her desired syntax for obtaining a better translated sentence, his or her desire is not directly reflected when using the known translation machine.
That is, the known translation machine allows the user to partially change the translation operation. However the user's possible adjustment is limited to the word or idiom level or the general trend of a part of the translating process. The user cannot choose a specific syntax to be used by the machine.
Therefore, if a user is very particular about grammar and requires that a translation be entirely grammatically correct, he/she could not, in the prior art, instruct the translator to translate with a syntax which corresponds to such a high level of grammatical correctness.